Combination of the PARPi and ARSi in advanced castration resistant prostate cancer: a review of the recent phase III trials.

Tumors with an impaired ability to repair DNA double-strand breaks by homologous recombination, including those with alterations in breast cancer 1 and 2 (BRCA1 and BRCA2) genes, are very sensitive to blocking DNA single-strand repair by inhibition of the poly (ADP-ribose) polymerase (PARP) enzyme. This provides the basis for a synthetic deadly strategy in the treatment of different types of cancer, such as prostate cancer (PCa). The phase 3 PROfound study was the first to lead to olaparib approval in patients with metastatic castration resistant PCa (mCRPC) and BRCA genes mutations. In recent years, the benefit of combination therapy consisted of a PARP inhibitor (PARPi) plus an androgen receptor signalling inhibitor (ARSi), was evaluated as first-line treatment of mCRPC, regardless of the mutational state of genes, participating in the homologous recombination repair (HRR). This review explores the role of PARPi in PCa and analyses the data of latest clinical trials exploring the PARPi-ARSi combinations, and how these results could change our clinical practice.

Real-world outcomes in patients with metastatic castration-resistant prostate cancer beyond progression after upfront androgen receptor signaling inhibitor.

BACKGROUND: Upfront androgen receptor signaling inhibitor (ARSI) along with androgen deprivation therapy is the current standard of care for metastatic castration-sensitive prostate cancer. However, evidence on second-line therapy after upfront ARSI is scarce. We aimed to evaluate the oncological outcome of ARSI versus docetaxel (DOC) after upfront ARSI therapy in a real-world clinical practice. METHODS: Subjects were metastatic castration-resistant prostate cancer (mCRPC) patients who had progressed within 2 years of upfront ARSI therapy and received ARSI (ARSI group) or DOC (DOC group) as a second-line therapy. Second-line progression-free survival (second-line PFS), and second-line overall survival (second-line OS) were assessed. Propensity score matching (PSM) was used to adjust the clinicopathological features and treatment patterns. RESULTS: A total of 101 mCRPC patients, 68 in the ARSI group, and 33 in the DOC group, were included in this analysis. Median second-line PFS was 6.3 months in the ARSI group and 4.9 months in the DOC group (p = 0.21). Median second-line OS was 25.0 months in the ARSI group and 14.2 months in the DOC group (p = 0.06). Prostate-specific antigen nadir ≤ 0.2 ng/ml during upfront ARSI therapy was significantly associated with improved second-line PFS. After PSM, no significant difference in second-line PFS and second-line OS were observed between the two groups. CONCLUSION: ARSI or DOC has comparable oncologic outcomes in terms of second-line PFS and second-line OS. Further prospective research with longer follow-ups will be needed to identify the optimal treatment after upfront ARSI therapy.

N-terminal domain of androgen receptor is a major therapeutic barrier and potential pharmacological target for treating castration resistant prostate cancer: a comprehensive review.

The incidence rate of prostate cancer (PCa) has risen by 3% per year from 2014 through 2019 in the United States. An estimated 34,700 people will die from PCa in 2023, corresponding to 95 deaths per day. Castration resistant prostate cancer (CRPC) is the leading cause of deaths among men with PCa. Androgen receptor (AR) plays a critical role in the development of CRPC. N-terminal domain (NTD) is the essential functional domain for AR transcriptional activation, in which modular activation function-1 (AF-1) is important for gene regulation and protein interactions. Over last 2 decades drug discovery against NTD has attracted interest for CRPC treatment. However, NTD is an intrinsically disordered domain without stable three-dimensional structure, which has so far hampered the development of drugs targeting this highly dynamic structure. Employing high throughput cell-based assays, small-molecule NTD inhibitors exhibit a variety of unexpected properties, ranging from specific binding to NTD, blocking AR transactivation, and suppressing oncogenic proliferation, which prompts its evaluation in clinical trials. Furthermore, molecular dynamics simulations reveal that compounds can induce the formation of collapsed helical states. Nevertheless, our knowledge of NTD structure has been limited to the primary sequence of amino acid chain and a few secondary structure motif, acting as a barrier for computational and pharmaceutical analysis to decipher dynamic conformation and drug-target interaction. In this review, we provide an overview on the sequence-structure-function relationships of NTD, including the polymorphism of mono-amino acid repeats, functional elements for transcription regulation, and modeled tertiary structure of NTD. Moreover, we summarize the activities and therapeutic potential of current NTD-targeting inhibitors and outline different experimental methods contributing to screening novel compounds. Finally, we discuss current directions for structure-based drug design and potential breakthroughs for exploring pharmacological motifs and pockets in NTD, which could contribute to the discovery of new NTD inhibitors.

Effect of deep testosterone reduction on the prognosis of metastatic prostate cancer with high-volume disease.

OBJECTIVE: This study aims to investigate the correlation between serum testosterone levels after one month of treatment and prognosis in patients with high-volume disease metastatic prostate cancer (mPCa) who are undergoing combined androgen blockade therapy (CAB). METHODS: The clinical data of 199 patients with high-volume disease mPCa, diagnosed through biopsy pathology and imaging, were retrospectively analyzed from January 2010 to October 2022 in the Department of Urology at the First Affiliated Hospital of Xinjiang Medical University. Among these patients, 111 cases had a deep reduction in serum testosterone (< 0.7 nmol/l) after one month of treatment, while 88 cases did not achieve a deep reduction (≥ 0.7 nmol/l). The study utilized the Kaplan-Meier method to plot survival curves and employed the multifactor COX regression model to analyze independent risk factors. The risk factors with a significance level of P < 0.05 in the multivariate analysis were included in the nomogram prediction model. The accuracy of the model was assessed using the ROC curve and the calibration curve, while the net benefit for patients was evaluated through the decision curve analysis (DCA). RESULTS: The group that achieved deep testosterone reduction(DTR) had a higher proportion of PSA < 0.2 ng/ml and a greater PSA decline rate after six months of treatment (P < 0.05). The group that achieved DTR and the group that did not achieve DTR had a progression to castration resistant prostate cancer(CRPC) time of 17.93 ± 6.68 months and 13.43 ± 6.12 months, respectively (P < 0.001). The median progression-free survival time for the 2 groups were 18 months and 12 months, respectively (P < 0.001). The median overall survival times were 57 months and 32 months, respectively (P < 0.001). The median progression-free survival times were 18, 15, and 10 months for the group that achieved DTR within 1 month, the group that achieved DTR beyond 1 month but within 1 year, and the group that did not achieve DTR within 1 year, respectively (P < 0.001), and the median survival times were 57, 45, and 26 months, respectively (P < 0.001). COX multivariate analysis revealed that a testosterone level of ≥ 0.7 nmol/l at 1 month of treatment is an independent risk factor for the progression to CRPC and prognosis in patients with high-volume disease mPCa (P < 0.05). The risk of death in patients with a testosterone level of ≥ 0.7 nmol/l at 1 month of treatment was 2.087 times higher than that of patients with a level of < 0.7 nmol/l (P < 0.05). A nomogram prediction model was developed using independent risk factors, with the area under the ROC curve (AUC) for progression-free survival (PFS) at 12, 15, 18, and 21 months being 0.788, 0.772, 0.760, and 0.739, respectively. For 3 and 5 years, the AUCs for overall survival (OS) were 0.691 and 0.624. The calibration curve demonstrated good consistency between the model's predicted values and the actual outcomes. CONCLUSION: Patients with high-volume disease mPCa who receive CAB treatment may experience extended progression-free survival and overall survival if their serum testosterone levels are below 0.7 nmol/l after one month of treatment. The longer it takes to achieve DTR, the worse the patient's prognosis may be. The nomogram prediction model developed in this study demonstrates good predictive ability in assessing the progression and prognosis of high-volume disease mPCa.

Treatment-induced stemness and lineage plasticity in driving prostate cancer therapy resistance.

Most human cancers are heterogeneous consisting of cancer cells at different epigenetic and transcriptional states and with distinct phenotypes, functions, and drug sensitivities. This inherent cancer cell heterogeneity contributes to tumor resistance to clinical treatment, especially the molecularly targeted therapies such as tyrosine kinase inhibitors (TKIs) and androgen receptor signaling inhibitors (ARSIs). Therapeutic interventions, in turn, induce lineage plasticity (also called lineage infidelity) in cancer cells that also drives therapy resistance. In this Perspective, we focus our discussions on cancer cell lineage plasticity manifested as treatment-induced switching of epithelial cancer cells to basal/stem-like, mesenchymal, and neural lineages. We employ prostate cancer (PCa) as the prime example to highlight ARSI-induced lineage plasticity during and towards development of castration-resistant PCa (CRPC). We further discuss how the tumor microenvironment (TME) influences therapy-induced lineage plasticity. Finally, we offer an updated summary on the regulators and mechanisms driving cancer cell lineage infidelity, which should be therapeutically targeted to extend the therapeutic window and improve patients' survival.

Opposing impact of hypertension/diabetes following hormone therapy initiation and preexisting statins on castration resistant progression of nonmetastatic prostate cancer: a multicenter study.

Hormone therapy, especially androgen deprivation therapy (ADT), is effective against prostate cancer (PC), whereas long-term ADT is a risk for metabolic/cardiovascular disorders including diabetes (DM), hypertension (HT) and dyslipidemia (DL), and might result in progression to castration-resistant prostate cancer (CRPC). We thus conducted a multicenter retrospective cohort study to ask whether CRPC progression would be associated positively with HT, DM or DL and negatively with statins prescribed for treatment of DL. In this study, 1,112 nonmetastatic PC patients undergoing ADT were enrolled. Univariate statistical analyses clearly showed significant association of HT or DM developing after ADT onset, though not preexisting HT or DM, with early CRPC progression. On the other hand, preexisting DL or statin use, but not newly developed DL or started statin prescriptions following ADT, was negatively associated with CRPC progression. Multivariate analysis revealed significant independent association of the newly developed DM or HT, or preexisting statin use with CRPC progression [adjusted hazard ratios (95% confidence intervals): 3.85 (1.65-8.98), p = 0.002; 2.75 (1.36-5.59), p = 0.005; 0.25 (0.09-0.72), p = 0.010, respectively]. Together, ADT-related development of HT or DM and preexisting statin use are considered to have positive and negative impact on CRPC progression, respectively.

NFYA-mediated promotion of castration-resistant prostate cancer progression through EGR4 regulation.

This research investigates the intricate involvement of nuclear Transcription Factor Y Subunit Alpha (NFYA) in the advancement of castration-resistant prostate cancer (CRPC) and its consequential impact on early Growth Response 4 (EGR4) expression. NFYA demonstrates a significant elevation in CRPC tissues and cell lines, displaying robust upregulation in metastatic prostate cancer (mPCa) samples, closely associated with the Gleason score. Immunohistochemistry validates heightened nuclear staining of NFYA in CRPC patients, highlighting its crucial role in the progression of advanced prostate cancer. Silencing NFYA through siRNA in androgen-independent cell lines markedly impedes cell growth and migration, emphasizing NFYA's pivotal role in promoting CRPC behavior. RNA-seq analysis identifies EGR4 as a downstream target of NFYA, with both genes consistently upregulated in CRPC. Validating this finding, heightened expression of EGR4 is observed in CRPC samples. In vivo studies utilizing a mouse model demonstrate that NFYA silencing substantially inhibits LNCaP-AI/22RV1shNFYA xenograft tumor growth, accompanied by reduced expression of EGR4 and Ki67. This comprehensive study reveals the multifaceted role of NFYA in CRPC progression, elucidates its downstream impact on EGR4, and underscores the therapeutic potential of targeting NFYA to inhibit CRPC growth in vivo. These findings contribute valuable insights into potential therapeutic strategies for managing CRPC.

Clinical significance of PSA dynamics in castration-sensitive prostate cancer treated with ARSI doublet therapy: A multicenter study.

BACKGROUND: Androgen receptor signaling inhibitors (ARSIs) have revolutionized the treatment of metastatic castration-sensitive prostate cancer (mCSPC). Prostate-specific antigen (PSA) dynamics, including PSA nadir, PSA response rate, and time to PSA nadir (TTN), are well-established markers of disease control. We evaluated the clinical significance of these PSA dynamics using data from a multicenter clinical database for mCSPC patients. METHODS: We conducted a multicenter retrospective study including 552 mCSPC patients treated with ARSI and ADT, and 262 patients treated with combined androgen blockade (CAB). PSA nadir, PSA response rate, and TTN were evaluated using predefined cut-offs. Clinicopathological data were collected and subsequently analyzed using multivariate Cox regression models to investigate impact of the PSA dynamics on oncological outcomes, including castration resistant prostate cancer free survival (CRPCFS), cancer-specific survival (CSS), and overall survival (OS). Propensity score matching (PSM) was used to minimize selection bias and balance baseline characteristics between treatment the groups. The achievement rates of low PSA nadir and high PSA response were then evaluated. RESULTS: In the ARSI cohort, 36.4% of patients achieved a PSA nadir of ≤ 0.02 ng/mL, and 65.8% attained a PSA response rate of ≥ 99 %. Notably, patients with a PSA nadir of ≤ 0.02 ng/mL, a PSA response rate ≥ 99%, and TTN > 12 months demonstrated significantly improved oncological outcomes. Multivariate analyses confirmed that these PSA dynamics were independent predictors of favorable oncological outcomes. A PSA nadir of ≤ 0.02 ng/mL was as an independent predictor of improved oncological outcomes compared to a nadir of > 0.2 ng/mL (CRPCFS: HR, 0.063; CSS: HR, 0.12; OS: HR, 0.15; P < 0.001). A PSA response rate of ≥ 99% compared to < 95%, also independently predicted more favorable outcomes (CRPCFS: HR, 0.29; CSS: HR, 0.26; OS: HR, 0.30; P < 0.001). Furthermore, a TTN > 12 months was also an independent predictor of improved survival compared to TTN ≤ 3 months (CRPCFS: HR, 0.12; CSS: HR, 0.08; OS: HR, 0.12; P < 0.001). PSM with a 1:1 ratio was associated with significantly higher rates of PSA nadir ≤ 0.02 ng/mL and PSA response rate ≥ 99% in the ARSI doublet group compared to the CAB group. CONCLUSIONS: Our study demonstrates that achieving a PSA nadir ≤ 0.02 ng/mL, a PSA response rate ≥ 99%, and a longer TTN are associated with significantly improved oncological outcomes. Furthermore, we elucidated how PSA dynamics differ between ARSI doublet therapy and CAB, highlighting the distinct characteristics of each. These findings provide valuable clinical information for guiding the management and prognosis of mCSPC in routine clinical practice.

Efficacy and Safety of Olaparib Plus Abiraterone Versus Placebo Plus Abiraterone in the First-line Treatment of Patients with Asymptomatic/Mildly Symptomatic and Symptomatic Metastatic Castration-resistant Prostate Cancer: Analyses from the Phase 3 PROpel Trial.

BACKGROUND AND OBJECTIVE: In PROpel (NCT03732820), olaparib + abiraterone resulted in a statistically significant radiographic progression-free survival (rPFS) benefit and numerically prolonged overall survival (OS) versus placebo + abiraterone in first-line (1L) metastatic castration-resistant prostate cancer (mCRPC) patients. Here, we report post hoc exploratory subgroup analyses in patients with asymptomatic/mildly symptomatic or symptomatic disease at baseline. METHODS: Patients were randomised 1:1 to olaparib (300 mg b.i.d.) or placebo with abiraterone (1000 mg o.d.) + prednisone/prednisolone (5 mg b.i.d.). For this post hoc exploratory analysis, patients with a Brief Pain Inventory-Short Form (BPI-SF) item 3 score of <4 and no opiate use were classified as asymptomatic/mildly symptomatic; those with a BPI-SF item 3 score of ≥4 and/or opiate use were classified as symptomatic. Subgroup analyses included investigator-assessed rPFS, OS, objective response rate, time to second progression or death, health-related quality of life, and safety. KEY FINDINGS AND LIMITATIONS: The median rPFS in asymptomatic/mildly symptomatic patients (n = 560) was 27.6 mo for olaparib + abiraterone versus 19.1 mo for placebo + abiraterone (hazard ratio [HR], 0.59; 95% confidence interval [CI], 0.46-0.76). For symptomatic patients (n = 183), equivalent values were 14.1 versus 13.8 mo (HR, 0.78; 95% CI, 0.54-1.13). At the final planned OS analysis, the median OS in asymptomatic/mildly symptomatic patients was not reached for olaparib + abiraterone versus 39.5 mo for placebo + abiraterone (HR, 0.77; 95% CI, 0.59-1.00). For symptomatic patients, equivalent values were 22.9 versus 22.8 mo (HR, 0.82; 95% CI, 0.58-1.16). Other outcomes showed no meaningful differences between the subgroups. CONCLUSIONS AND CLINICAL IMPLICATIONS: Olaparib + abiraterone provided efficacy benefits in 1L mCRPC patients with either asymptomatic/mildly symptomatic or symptomatic disease. A larger benefit occurred in asymptomatic/mildly symptomatic patients. PATIENT SUMMARY: PROpel, a phase 3 clinical trial, looked at whether combining olaparib with abiraterone delays the progression of patients' cancer compared with placebo plus abiraterone. Patients with or without pain symptoms associated with metastatic castration-resistant prostate cancer were eligible for enrolment into the trial. Results showed that olaparib plus abiraterone reduced the risk of disease progression and death, with a larger benefit observed in patients without or with mild pain symptoms than in those with pain symptoms.

Comparative Transcriptomes of Canine and Human Prostate Cancers Identify Mediators of Castration Resistance.

Prostate cancer continues to be one of the most lethal cancers in men. While androgen deprivation therapy is initially effective in treating prostate cancer, most cases of advanced prostate cancer eventually progress to castration-resistant prostate cancer (CRPC), which is incurable. Similarly, the most aggressive form of prostatic carcinoma occurs in dogs that have been castrated. To identify molecular similarities between canine prostate cancer and human CRPC, we performed a comparative analysis of gene expression profiles. Through this transcriptomic analysis, we found that prostatic carcinoma in castrated dogs demonstrates an androgen-indifferent phenotype, characterised by low-androgen receptor and neuroendocrine-associated genes. Notably, we identified two genes, ISG15 and AZGP1, that were consistently up- and down-regulated, respectively, in both canine prostatic carcinoma and human CRPC. Additionally, we identified several other genes, including GPX3, S100P and IFITM1, that exhibited similar expression patterns in both species. Protein-protein interaction network analysis demonstrated that these five genes were part of a larger network of interferon-induced genes, suggesting that they may act together in signalling pathways that are disrupted in prostate cancer. Accordingly, our findings suggest that the interferon pathway may play a role in the development and progression of CRPC in both dogs and humans and chart a new therapeutic approach.

Acetate utilization promotes hormone therapy resistance in prostate cancer through neuroendocrine differentiation.

AIMS: Tumor fatty acid (FA) metabolic plasticity plays a pivotal role in resistance to therapy and poses limitations to anticancer strategies. In this study, our aim is to uncover the role of acetate metabolism in neurodifferentiation (NED)-mediated castration-resistant prostate cancer (CRPC). METHODS: We conducted analyses using LC-MS/MS on clinical prostate cancer tissue before and after hormone therapy. We established tumor xenograft mouse models, primary tumor cells, and human-derived organoids to detect the novel mechanism of NED and to identify potential therapies. RESULTS: The hormone therapy-induced upregulation of acetate metabolism was mediated by acyl-CoA synthetase short-chain family member 2 (ACSS2), which increased c-MYC expression for NED induction. Notably, combined treatment with an ACSS2 inhibitor and enzalutamide significantly reduced the xenograft tumor volume. CONCLUSION: Our findings uncovered the critical role of acetate metabolism in NED-mediated CRPC and suggest that ACSS2 inhibitors may represent a novel, low-toxicity strategy when combined with hormone therapy for treating patients with NED-mediated CRPC.

Cystine urolithiasis-free duration after first occurrence and treatment is longer for castrated dogs than for sexually intact male dogs.

OBJECTIVE: To evaluate outcome in 60 dogs with cystine urolithiasis treated with surgical removal with and without castration and postoperative therapeutic diet to determine frequency of recurrence and urolith-free duration. METHODS: Patient records were reviewed for dogs with documented cystine urolithiasis from September 2010 to December 2020. Medical records, client interviews, and referring veterinarians were contacted to document the absence of clinical signs associated with subsequent urolith formation and to evaluate risk factors for urolith reoccurrence. RESULTS: 80 patients were identified with cystine uroliths, with 60 qualifying for inclusion in the study. Seven dogs were neutered prior to surgery, and 25 dogs were neutered at the time of the first surgery. Recurrence occurred in 20 dogs; 17 of those patients were intact (85%) at the time of recurrent urinary signs. Of the 20 dogs with recurrence, 50% (10 of 20) were being treated with dietary modifications. CONCLUSIONS: The risk of recurrence among neutered pets was 23% versus 47% for intact pets, but this difference was not statistically significant; however, neutered pets had a longer urolithiasis-free duration. There was no statistically significant difference in risk of recurrence and urolith-free duration between pets with and without therapeutic diet management, (30% vs 32.5%) respectively. Multivariant analysis showed no significant interaction between surgical intervention with therapeutic diet, with nonsignificant hazard ratios (HRs) for neuter status (HR = 0.503), diet (HR = 1.056), and their interaction (HR = 4.32 to 9). CLINICAL RELEVANCE: Sexually intact (vs castrated) male dogs should be monitored more closely for recurrence of surgical cystine urolithiasis.

Best Patient Care Practices for Administering PSMA-Targeted Radiopharmaceutical Therapy.

Optimal patient management protocols for metastatic castration-resistant prostate cancer (mCRPC) are poorly defined and even further complexified with new therapy approvals, such as radiopharmaceuticals. The prostate-specific membrane antigen (PSMA)-targeted agent 177Lu vipivotide tetraxetan ([177Lu]Lu-PSMA-617), approved after the phase III VISION study, presents physicians with additional aspects of patient management, including specific adverse event (AE) monitoring and management, as well as radiation safety. Drawing on our experience as VISION study investigators, here we provide guidance on best practices for delivering PSMA-targeted radiopharmaceutical therapy (RPT) to patients with mCRPC. After a comprehensive review of published evidence and guidelines on RPT management in prostate cancer, we identified educational gaps in managing the radiation safety and AEs associated with [177Lu]Lu-PSMA-617. Our results showed that providing sufficient education on AEs (e.g., fatigue and dry mouth) and radiation safety principles is key to effective delivery and management of patient expectations. Patient counseling by health care professionals, across disciplines, is a cornerstone of optimal patient management during PSMA-targeted RPT. Multidisciplinary collaboration is crucial, and physicians must adhere to radiation safety protocols and counsel patients on radiation safety considerations. Treatment with [177Lu]Lu-PSMA-617 is generally well tolerated; however, additional interventions may be required, such as dosing modification, medications, or transfusions. Urinary incontinence can be challenging in the context of radiation safety. Multidisciplinary collaboration between medical oncologists and nuclear medicine teams ensures that patients are monitored and managed safely and efficiently. In clinical practice, the benefit-to-risk ratio should always be evaluated on a case-by-case basis.

Enzalutamide in metastatic hormone-sensitive prostate cancer: A plain language summary of the ARCHES and ENZAMET follow-up studies.

WHAT IS THIS SUMMARY ABOUT?: This summary includes information from the ARCHES and ENZAMET follow-up studies. Both studies looked at enzalutamide treatment for people with metastatic hormone-sensitive prostate cancer (known as mHSPC). In ARCHES, researchers compared the medications enzalutamide + androgen deprivation therapy (known as ADT) with placebo + ADT. In ENZAMET, researchers compared enzalutamide + ADT with standard treatment + ADT. Some people in ENZAMET also took enzalutamide with docetaxel (a chemotherapy treatment). In both studies, researchers wanted to find out if enzalutamide helps people with mHSPC live longer. WHAT ARE THE KEY TAKEAWAYS?: In both studies, researchers found that people with mHSPC who took enzalutamide lived longer than people who did not. People who took enzalutamide also lived longer without their cancer getting worse. The results were mostly similar in groups of people dependingon when and where their cancer was found. Researchers did not find any new safety concerns. WHAT WERE THE MAIN CONCLUSIONS?: People with mHSPC may benefit from long-term treatment with enzalutamide + ADT. They may also benefit from taking enzalutamide with other treatments, like docetaxel. It may be better for people with mHSPC to have enzalutamide treatment before their cancer gets worse, rather than waiting. These people and their doctors should carefully consider the benefits and risks of each treatment to make a joint decision for treating mHSPC.Clinical Trial Registration: NCT02677896 (ARCHES), NCT02446405 (ENZAMET) (ClinicalTrials.gov).

The Role of CENPK Splice Variant in Abiraterone Response in Metastatic Castration-Resistant Prostate Cancer.

Most patients with metastatic prostate cancer eventually develop resistance to primary androgen deprivation therapy. To identify predictive biomarker for Abiraterone acetate/prednisone resistance, we screened alternative splice variants between responders and non-responders from the PROMOTE clinical study and pinned down the most significant variant, CENPK-delta8. Through preclinical patient-derived mouse xenograft (PDX) and 3D organoids obtained from responders and non-responders, as well as in vitro models, aberrant CENPK-delta8 expression was determined to link to drug resistance via enhanced migration and proliferation. The FLNA and FLOT1 were observed to specifically bind to CENK-delta8 rather than wild-type CENPK, underscoring the role of CENPK-delta8 in cytoskeleton organization and cell migration. Our study, leveraging data from the PROMOTE study, TCGA, and TCGA SpliceReq databases, highlights the important function of alternative splice variants in drug response and their potential to be prognostic biomarkers for improving individual therapeutic outcomes in precision medicine.

Matched-pair analysis of mCRPC patients receiving 177Lu-labeled PSMA-targeted radioligand therapy in a 4-week versus 6-week treatment interval.

BACKGROUND: The optimal regimen for 177Lu-labeled prostate-specific membrane antigen-targeted radioligand therapy, including treatment intervals, remains under study, with evidence suggesting shorter intervals could benefit patients with high disease volume and rapid progression. This retrospective analysis evaluated treatment toxicity, PSA response, PSA-progression-free survival (PSA-PFS), and overall survival (OS) in matched cohorts of mCRPC patients receiving 177Lu-PSMA-RLT at 4-week versus 6-week intervals. RESULTS: A PSA response (PSA decline ≥ 50%) was achieved in 47.8% and 21.7% of patients in the 4-week and 6-week treatment interval groups, respectively (p = 0.12). There was a trend towards longer PSA-PFS in the 4-week group compared to the 6-week group (median PSA-PFS, 26.0 weeks vs. 18.0 weeks; HR 0.6; p = 0.2). Although not statistically significant, there was a trend towards shorter OS in the 4-week group compared to the 6-week group (median OS, 15.1 months vs. 18.4 months; HR 1.3; p = 0.5). The 4-week group had a significantly greater decrease in leucocyte and platelet counts compared to the 6-week group (38.5% vs. 18.2% and 26.7% vs. 10.7%; p = 0.047 and p = 0.02). Severe adverse events were modest in both groups. CONCLUSIONS: Intensifying treatment intervals from 6 weeks to 4 weeks showed some improvements in PSA response and PSA-PFS for mCRPC patients, but did not significantly affect OS. Additionally, bone marrow reserve was significantly reduced with the intensified regimen. Therefore, the overall benefit remains uncertain, and further prospective studies are needed to compare 4-week and 6-week intervals regarding toxicity, treatment response, and outcome.

Novel astatine (211At)-labelled prostate-specific membrane antigen ligand with a neopentyl-glycol structure: evaluation of stability, efficacy, and safety using a prostate cancer xenograft model.

PURPOSE: Prostate-specific membrane antigen (PSMA)-targeted alpha therapy is considered a promising alternative treatment for metastatic castration-resistant prostate cancer (mCRPC). Though astatine-211 (211At) is potentially useful alpha-emitter producible by cyclotrons, its clinical application has been limited by instability and a tendency to deastatination in vivo. To overcome these challenges, we developed [211At]At-NpG-PSMA, a novel PSMA ligand with a neopentyl-glycol structure that enhances in vivo stability against deastatination. This study aimed to evaluate the stability, anti-tumour effect, and safety of [211At]At-NpG-PSMA in mice. METHODS: Xenograft models were prepared by subcutaneous transplantation of PSMA-positive PC-3 PIP cells into BALB/c nu/nu mice. [211At]At-NpG-PSMA was administered to assess biodistribution, and the anti-tumour effect was evaluated at doses of 0.32, 1.00 and 1.93 MBq in comparison with saline. Histopathological examinations were performed to evaluate damage to normal organs. RESULTS: [211At]At-NpG-PSMA demonstrated high tumour uptake (42.0 ± 13.1%ID/g at 3 h) with minimal uptake in non-target tissues, including thyroid, stomach and salivary grands (0.28 ± 0.20%ID, 0.71 ± 0.12%ID/g and 0.88 ± 0.10%ID/g at 3 h, respectively). A dose-dependent anti-tumour effect was observed, with tumour volumes increasing by 796.0 ± 437.6% in the control versus 161.0 ± 213.4%, -76.4 ± 19.2% and - 59.5 ± 41.6% in the 0.32, 1.00 and 1.93 MBq groups, respectively, by day 15. Mild renal tubule regeneration was noted in the 1.00 MBq group. CONCLUSION: [211At]At-NpG-PSMA demonstrated significant stability in vivo and anti-tumour effects with minimal side effects, indicating its potential as a new therapeutic drug for PSMA-targeted alpha therapy in mCRPC.

Latin American Challenges and Recommendations for Poly Adenosine Diphosphate Ribose Polymerase Inhibitor Treatment in Metastatic Castration Resistant Prostate Cancer: An Expert Overview.

In Latin America, prostate cancer is the third most common cancer overall and the most common in men, with the highest mortality rate of all cancers. In 2022, there were approximately 22,985 new prostate cancer cases and 61,056 deaths from prostate cancer in the region. Patients with metastatic disease that is resistant to cure by castration now have multiple therapeutic options, including poly-ADP ribose polymerase inhibitors. These treatment advances present new challenges, such as developing monitoring protocols for early detection of disease progression to castration resistance. The Americas Health Foundation organized a 3-day meeting with 8 regional oncologists and pathologists to create a paper on metastatic castration-resistant prostate cancer diagnosis and therapy, including the new poly-ADP ribose polymerase inhibitors. The panel examined metastatic castration-resistant prostate cancer in Latin America and recommended ways to improve patient care using published literature and their expertise. Gene mutations play an important role in prostate cancer development. Precision medicine innovations highlight the importance of genotyping DNA variants and tumor biomarkers for targeted treatment. Access to appropriate genetic testing is difficult, medications are available but expensive, and there is a lack of infrastructure and regulatory frameworks that prevent patients from benefiting from innovative therapies. The panel recommends developing a population database and biobank and creating tumor tissue collection, processing, and storage facilities. Multi-stakeholder collaboration is needed to integrate the information gathered, train staff, select target populations, improve patient accessibility, and reduce the cost burden of drugs, genetic counselors, and cancer geneticists in Latin America. Collaboration is essential among healthcare professionals, policymakers, patient advocacy groups, pharmaceutical companies, and international organizations to address these challenges and needs in Latin America.

Prevalence and management of castration-resistant prostate cancer of unknown metastatic status in the real-world setting: The AfroDiTA study.

BACKGROUND: Early identification and management of metastases in prostate cancer (PC) patients is crucial. This study aimed to describe the nonpharmacological management and characteristics of patients with castration-resistant PC with unknown metastatic status (CRPC-MX) and estimate their prevalence in Spain. METHODS: Cross-sectional, multicenter, real-world study including adult (≥18 years) CRPC-MX patients from 46 Urology services. In a first phase, patients on continuous ADT for ≥6 months were screened and classified as hormone-sensitive PC (HSPC), castration-resistant PC (CRPC), and unknown hormonal status, with metastases (M1), without (M0) and unknown metastatic status (MX) using an ad hoc designed algorithm. In Phase 2, 15 months (m) after Phase 1, all patients on ADT were reviewed and reclassified again using the algorithm. RESULTS: Among 6169 eligible PC patients, 294 (4.8%) were classified as CRPC-MX, which decreased to 179 of 4050 (4.4%) 15 m after study initiation. We included 103 CRPC-MX patients with a median age at diagnosis of 75.4 years (IQR: 67.8, 80.4); 26 (25.2%) lacked a histological diagnosis, and only 25 (24.5%) received treatment with curative intent, despite ECOG being ≤1 at inclusion in 83.5%. In the 15 m before inclusion, most CRPC-MX patients had <5 prostate-specific antigen (PSA) determinations (80.6%) and no imaging (63.1%). After CRPC-MX identification (15 m after inclusion), metastatic status was assessed in 55.4%, with an increased number of patients with ≥5 PSA determinations (P = 0.0357), visits per patient (P < 0.0001), patients with some imaging test (P < 0.0001), imaging tests/patient (P < 0.0001), and visits to onco-urology specialized consultation units (52.0% before and 79.2% after). CONCLUSION: A substantial proportion of PC patients on ADT in the real-world setting are not appropriately followed up. Identification of CRPC-MX patients raised awareness among physicians and improved their adherence to guidelines, resulting in improved care for these patients.

Bipolar androgen therapy for treatment of metastatic castration-resistant prostate cancer: A case series.

INTRODUCTION: Advanced prostate cancer treatment has improved with androgen receptor signaling inhibitors (ARPI), yet many patients develop metastatic castration-resistant prostate cancer (mCRPC), characterized by sustained androgen receptor (AR) signaling. Bipolar androgen therapy (BAT) introduces supraphysiologic testosterone levels to inhibit tumor growth, offering novel treatment for mCRPC by exploiting AR-dependent mechanisms. CASE PRESENTATIONS: Case 1: A 53-year-old man with mCRPC, post multiple systemic therapies, initiated BAT and pembrolizumab, achieving PSA reduction and improved quality of life before progression. The patient exhibited AR amplification, which may have contributed to favorable response to BAT. Case 2: A 73-year-old man with recurrent prostate cancer, stable on ADT and abiraterone, experienced PSA decline with BAT to an undetectable level, maintaining stability post-therapy discontinuation. Case 3: A 73-year-old man with metastatic prostate cancer, initially resistant to enzalutamide, achieved clinical benefit and disease control with BAT, although he did not meet PSA response criteria, patient had remarkable response upon enzalutamide rechallenge. Case 4: A 90-year-old man with localized prostate cancer, refractory to multiple treatments, experienced symptom relief and PSA reduction with BAT before progression. CONCLUSION: BAT represents a promising treatment strategy for mCRPC. This case series underscores BAT's potential to induce significant clinical and biochemical responses, resensitize tumors to ARPIs, and improve patients' quality of life. Despite eventual progression in some cases, BAT offers a period of disease control. Further research is needed to optimize patient selection and understand the molecular determinants of BAT responsiveness.